How to set-up somebody? Any ideas?

Ok, so in my free e-book, an young adult (25 years old) wish to revenge on some "back street boys".
Like gans, but more stupid , just dangerous. Not involved into drugs,etc.

He wish to do this because he suffered a false allegation, one idiot wished to take his girl friend.
Those guys because they had the balls and they were "gang style" boys falsy allged with a robber in progress, that never took actually place. Back in 2008 , so not to many "cams" on streets ,etc

All right till here... but how could easy setup that asshole up? he can't just put drugs into his car and call 911, they will not simply "not eat" without an court order.

A 25 year old man wants to take revenge on a group of 5 men who are in a gang-like group because they falsely accused him of something (drug abuse/possession/distribution). This was all for the sake of getting his girlfriend. What you want to know is how you should set up the false accusations - what should the gang do to get him falsely sent to jail/prison?

He can put a weapon in the glove compartment or under the seats of their car, then report them to the police for a crime (could be a bogus one) anonymously. The police would go after them and consider them armed and dangerous hence circumventing the warrant issue. However i am not sure on the workings of the legal/police system in Romania, if you are writing about Romania, and i may be mistaken.

Yeah, or beat them up. You don't need balls to do that because you don't have to go head-to-head with 'em: just put on a ski-mask so they don't know it's you, stalk one guy, follow him home, and while he's digging out his keys (or goes to take out the trash, something that has his attention), knock him out (maybe by using a weapon), and while he's unconscious, kick and stomp the crap out of him. Then on to the next guy.